9mm (20 marKS) 1.1 From a random sample of 250 owners of medium-sized motor vehicles, it was found that their average monthly car insurance premium for a full comprehensive cover was R550. Assuming the population standard deviation is R55 per month and the insurance premiums are normally distributed: 1.1.1 construct the 95% confidence interval for the average monthly premiums for owners of medium-sized vehicles and interpret the result. (3) 1.1.2 If the sample size is increased to 500 car owners and the population standard deviation becomes R58, estimate the 90% confidence of the total monthly premium of the company. Interpret your results. (7)